Adjustable trailing arms?

[JB21]

I've got hardrace adjustable upper and lower trailing arms but just don't get what they actually adjust?

I have a knock coming from the lower arm on the rose joint end so was going was going to attempt to lengthen the arm to see if gets rid of the knocking.

I just don't want the adjustment to knock out my rear alignment?

[shnazzle]

I've got hardrace adjustable upper and lower trailing arms but just don't get what they actually adjust?

I have a knock coming from the lower arm on the rose joint end so was going was going to attempt to lengthen the arm to see if gets rid of the knocking.

I just don't want the adjustment to knock out my rear alignment?

They change camber. Which in turn changes toe. So yes, you will mess with your alignment.

[JB21]

I've got hardrace adjustable upper and lower trailing arms but just don't get what they actually adjust?

I have a knock coming from the lower arm on the rose joint end so was going was going to attempt to lengthen the arm to see if gets rid of the knocking.

I just don't want the adjustment to knock out my rear alignment?

They change camber. Which in turn changes toe. So yes, you will mess with your alignment.

Not sure how can they change camber when they are trailing? The car also has hardrace adjustable toe 'control' arms but the trailing arms defo dont adjust camber as I tried to adjust them for camber before going for alignment.

[Call the midlife!]

I'm fairly confident the standard arms restrict the amount of camber you can dial in, the Hardrace wind out longer than standard so let the hubs kick out a bit more.

[JB21]

Just watched a spyder Lee video and it looks like the lower arms adjust the position of the wheel front to back. So tighten to the front of the car and it will pull the wheel towards the front and going the opposite way push the wheel back.

Don't see the point though.

[shnazzle]

Guess it changes the caster angle. Don't see how that's applicable to the rear though.
Never heard of adjustable trailing arms. I assumed you meant the "camber" arms

Edit: having looked at them fitted to the car, they are to increase camber.
If you were to lengthen one arm for more camber (excessive camber imo)but left the front one as-is, the hub would bent inwards, creating massive toe inwards. So you have to push the hub backwards, as it were, so that you can keep the mad camber but not have the toe effect.

That's my theory anyway

[JB21]

I've got a feeling the knocking is due to the bolt not being thick enough for the rose joint hole hence the knocking with suspension travel.

[thetyrant]

I have the hardrace rear toe control arms which came on car, annoyingly it doesnt really make toe adjustments much easier as you cant get to inner lock nut due to crossmember design!, my car is currently toe'ing out a smidge after removing all the arms during engine swaps etc and wanted it back to my usual Zero before next event but havent got time to mess about with the oe eccentric bolt now so will just leave it for this on and see how i go, it certainly turns in well!.

Other 2 arms work together as mentioned, so you length the middle one push hub out and give more camber but then also need to lengthen the trailing arm (front diagonal one) to push wheel back into postion and correct the toe as well as the toe control arm as well.

Knocking could be the joints worn but check all bolts and locknuts are tight as well.
 

[Dev]

There is a company called Battlefield that made these adjustable arms for our car. They were built very well and are mostly used for racing where you can have more adjustment. The Battlefield arms are expensive for a good reason because the spherical joints are built to a high degree. Later on the Chinese decided to knock off these arms and were not built as well as a few had them come lose from the joint which is dangerous.  The company supposedly added dust boots to solve this issue but who knows.
 
I had a pair of the toe arms that I was just about to install  and after hearing about the issue I sold the revised version that I had with full disclosure. 

 The drawbacks with these arms are harshness and noise from the joints since there is no rubber.  The other drawback is an increase in unsprung weight and if you do hit a bad bump it will transfer that energy to another area of the car and damage it.  I have seen MR-S cars that had bent control arms and once they were replaced all was well but if they didn't bend the energy would have been transferred somewhere else and it might end up as  irreversible frame damage.

The choice is yours but this is a modification that I will only do if I was racing and needed a specific alignment that I cant get with the OEM arms.



 

[shnazzle]

There is a company called Battlefield that made these adjustable arms for our car. They were built very well and are mostly used for racing where you can have more adjustment. The Battlefield arms are expensive for a good reason because the spherical joints are built to a high degree. Later on the Chinese decided to knock off these arms and were not built as well as a few had them come lose from the joint which is dangerous.  The company supposedly added dust boots to solve this issue but who knows.
 
I had a pair of the toe arms that I was just about to install  and after hearing about the issue I sold the revised version that I had with full disclosure. 

 The drawbacks with these arms are harshness and noise from the joints since there is no rubber.  The other drawback is an increase in unsprung weight and if you do hit a bad bump it will transfer that energy to another area of the car and damage it.  I have seen MR-S cars that had bent control arms and once they were replaced all was well but if they didn't bend the energy would have been transferred somewhere else and it might end up as  irreversible frame damage.

The choice is yours but this is a modification that I will only do if I was racing and needed a specific alignment that I cant get with the OEM arms.



 

I've been tempted by hardrace arms in the past. It's the stiffness and vibrations that kept me away. 


I had this conversation with the guys at AK Automotive funnily enough. They said they have them on race cars but basically it's not uncommon at all for something to bend during a race. They just use the arms to adjust the wheels to counteract the bent steel until it's no longer feasible to do so. Then they fix the area in question.